Composite coatings formed on the PEO-layers with the use of solutions of tetrafluoroethylene telomers

• Published in: Surface & coatings technology Vol. 346; pp. 53 - 62
• Main Authors: Gnedenkov, S.V., Sinebryukhov, S.L., Mashtalyar, D.V., Nadaraia, K.V., Kiryukhin, D.P., Kichigina, G.A., Kushch, P.P., Buznik, V.M.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 25-07-2018; Elsevier BV
• Subjects: Alloys; Chemical compounds; Coating effects; Comparative studies; Composite coatings; Contact angle; Corrosion currents; Ethyl acetate; Freons; Magnesium; Magnesium alloys; Magnesium base alloys; Manganese; Morphology; Oxidation; Plasma electrolytic oxidation; Polymers; Protective coatings; Telomeric solution; Tribology; Wear resistance; Wettability; Telomeric solution; Composite coatings; Plasma electrolytic oxidation; Protective coatings; Magnesium alloys
• ISSN: 0257-8972; 1879-3347
• DOI: 10.1016/j.surfcoat.2018.04.036

A method of the formation of the composite polymer-containing coatings on a MA8 magnesium alloy (Mg-Mn-Ce system) pretreated by the plasma electrolytic oxidation with subsequent application of the organofluorine component such as telomeric tetrafluoroethylene (TFE) solutions in pentafluorochlorobenzene, ethyl acetate and trifluorotrichlorethane (Freon 113) was developed. A comparative study of the morphological, electrochemical, and tribological characteristics and wettability of the formed protective layers has been carried out. It has been shown that application of polymeric material on the base PEO-coating provides a significant effect on the morphology and properties of samples surface. The data of electrochemical studies of composite coatings indicate more than 38-fold the decrease of the corrosion current density (IC = 6.3 × 10−9 A cm−2) as compared to the base PEO-coating. It has been found that the best corrosion properties are demonstrated by the samples formed in the TFE telomeric solution in pentafluorochlorobenzene. Evaluation of the wear resistance of composite layers revealed a decrease in wear (4.6 × 10−5 mm3 (N m)−1) of composite coatings by 2 orders of magnitude in comparison with the PEO-coating. The highest wearproof effect has been obtained by the coatings formed using TFE telomeric solution in Freon 113. The contact angle for formed composite layers attains to 142 ± 2°; such a result has been demonstrated by the composite layers obtained using TFE telomeric solution in ethyl acetate.
[Display omitted]
•Composite coatings (CC) with short-time high protective properties were obtained.•The influence of different types of telomers on CCs properties was investigated.•CC, obtained using telomeric solution, have hydrophobic properties.